Water turbine



Aug. 4, 1925,

E-. BANKI WATER TURBINE Filed Feb. 21. 1925 Ba nki r 1%. n e m T.

Elem

A aiforney Patented Aug. 4, 1925.

UNITED STATES ELEMER BANKI, or BUDAPEST, HUNGARY.

WATER TURBINE.

Application filed February 21, 1925. Serial No. 10,851.

To all whom it may concern:

Be it known that I, ELEMI IR BANKI, a subject of the Kingdom of Hungary, residing at Budapest, Hungary, have invented certain new and useful Improvements in later Turbines, of which the following is a specification.

This invention relates to water turbines of the type in which the vanes occupy only a circumferential ring surrounding a relatively large free central space traversed by the water jet which both enters and is discharged by the outer ends of the vanes. The object of the invention is to provide a turbine of that type which will receive and efliciently utilize the energy of largely variable quantities of water, and which will not suffer any essential loss of efficiency, when back-surge or reflux takes place as a result of congestion in the discharge passage.

Another object of the invention is to increase the draught capacity and the output of such turbines.

It has already been proposed to associate with turbines of the type described a regu lating device permitting to vary the thickness of the impact jet in the circumferential direction of the drum without essentially altering the angle of admission. However, such variation of the admission was hitherto kept within rather narrow limits, and it has become a deeply rooted belief that the arc of admission must not be expanded beyond the limit at which the water jet in traversing the open central space on the one side of the shaft passes near the shaft but does not yet reach it.

I have now discovered that it is not necessary to persist in the condition formerly considered as unshakeable according to which the water stream has to traverse the open central space of the drum without reaching the shaft. Theoretical deliberation led to the fact proved also by experiments that in a water stream traversing the open central space so as to extend upon both sides of the shaft, there arise about the rotating shaft stream lines involving only inconsiderable losses of energy so that a turbine of the type described will work very well also with the shaft rotating not in air but in the water stream.

So long as the increase of the admission are does not reach the further limit beyond which the water stream passing through the interior of the drum has not room enough in the free central space so that its exterior threads are compelled to return and flow out, without crossing the central space, between the same vanes between which they entered, the turbine will work substantially in the same manner and with the same efficiency as when the stream crosses the central space on the one side of the shaft without touching the latter, except that some pressure above atmospheric will arise in the interior of the drum. Beyond this limit, high pressure will arise in the interior of the drum, and the discharged stream will fill all such passages between the vanes as are not obstructed. In consequence of the, fact that some of the water threads will not cross the interior of the drum, such threads will work with diminished efficiency, but the efficiency of the whole turbine will not suffer any essential loss, since the overwhelming majority of the threads will work with complete efficiency.

If the water stream fills all the passages between the vanes on the outlet side of the drum, back-surge or reflux in the discharge passage can have no: effect on the turbine except that the terminal velocity will diminish. This velocity is, however, lost as regards the utilization of the energy of the water by the turbine in all turbines. W'hereas if the discharged jet fills only a few passages between the vanes as in the known turbines of the type in question, the efliciency is greatly affected by a back-surge or reflux in the discharge passage on account of the. idly revolving vanes acting as a pump and thereby consuming much energy.

. Therefore, I associate with the turbine of the type described a regulating device which is so constructed as to permit the short are of admission corresponding to the passage of the stream through the central space on the one side of the shaft without reaching the latter, to be expanded to such an extent that the shaft is flooded by the stream traversing the interior of the drum. Hereby I am enabled to increase the output with increase of the load to an extent which has been, hitherto, thought unattainable with such turbines. A further development of my discovery, I may amplify the extent of increasing the arc of admission so far as to cause the interior of the drum to be filled by the water stream, the discharge taking place through all such passages between the vanes as are not obstructed. Hereby I am enabled to increase the output and the draught capacity to the maximum limit that may be conceived, and I obtain a turbine which will work with excellent eiliciency also in case of a back-surge or reflux arising in the d scharge passage.

In the accompanying drawings. both figures show the same embodiment of my in vention in a cross section at right angles to the'shaft. Fig. 1 shows the turbine with the regulating device adjusted for small admission, the turbine workin thereby in the known manner. Fig. 2 shows the turbine with the regulating device adjusted for the maximum admission. 3

The interior of the turbine drum a-- carrying vanes -Z)- is entirely free, except that the shaft c extends along the axis of the drum. The drum is enclosed in a casing -(Z comprising also the admission and discharge channels marked -cZ and d respectively. The chute forming the back of the admission channel has the form of a logarithmic spiral in order to convey all threads of the water stream at substantially equal angles and on the shortest way onto the vanes. Close above the drum aa flap --e is arranged in the admission channel (Z The quandrangular shaft-e of this flap is rotatably mounted in the side walls of thecasing --.-cZ- One end of the shaft -6 projects beyond the side Wall of the casing -(Z-- and is there associated with known'means'for rotating and fixing it in the several positions of rotation. The blade of the flap cforms a continuation of the front wall of the admission channel (Z in the shape of alogarithmic spiral. The hub of the flap has a lug e which strikes against a stop surface on the casing when the flap reaches its extreme position corresponding to the maximum admission. The stream lines -'-f indicate the paths of the several Water threads.

In the position of the flap eas shown in Fig. l, the flap will serve to determine only the thickness of the admitted stream so that the latter is guided only on the one side by the chute. Practical experience has confirmedthat for a thin stream of water such one-sided guidance suffices.

In the extreme position of the flap ccorresponding to the maximum admission and shown in Fig. 2, the free end of the flap blade fits to the circumference of the drum so that the admitted stream having a considerablethickness is'guided on both sides up to the entry at the outer ends of the vanes, the admission of all water threads at the right angle being thereby ensured.

It will be understood that I do not wish to be limited to the particular form and construction of the regulating device as above described so that turbines of the type described, if provided with any regulating device permitting to amplify the arc of admission beyond the limit above exactly defined, fall within the scope of my invention.

\Vhat I claim is 1. The combination of a water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a free central space surrounded by said vanes, a shaft in the centre of said free space, and an admission channel having guiding walls so curved as to direct all threads oi the water stream at substantially equa angles onto a circumferexr tial portion of the drum, with regulating means permitting the arc of admission to be amplified to such an extent that the shaft is flooded by the stream traversing said central space.

2. The combination of a water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a free central space surrounded by said vanes, a shaft in the centre of said free space, and an admission channel having guiding walls so curved as to direct all threads of the water stream at substantially equal angles onto a circumferential portion of the drum, with regulating means permitting the arc of admission to be amplified to such an extent that the water stream fills out said central space. i

3. The combination of a Water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a free central s ace surrounded by said vanes, a shaft in t 1e centre of said free space, an admission channel having guiding walls so curved as to direct all threads of the water stream at substantially equal angles onto a circumferential portion of the drum, and a discharge channel joined to another circumferential por tion of the drum, with regulating means permitting the arc of admission to be ampli; lied to such an extent that discharge takes place through all such passages between said vanes as have direct communication with said discharge channel.

4:. A water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a, tree central space within said series of vanes, a shaft in the centre of said space, an admission channel having its back wall curved near the drum in the form of a loga rithmic spiral, and an adjustable flap post. tioned in said admission channel so as to form a continuation of the front wall of said channel the shape of a logarithmic spiral.

5. A water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a tree central space within said series of vanes, a shaft in the centre of said' space,

an admission channel having its back wall curved near the drum in the form of a logarithmic spiral, and an adjustable flap positioned in said admission channel so as to form a continuation of the front wall of said channel in the shape of a logarithmic spiral and permit the arc of admission to be amplified to such an extent that the shaft is flooded by the stream traversing said central space.

6. A water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a free central space Within said series of vanes, a shaft in the centre of said space, an admission channel having its back wall curved near the drum in the form of a logarithmic spiral, and an adjustable flap positioned in said admission channel so as to form a continuation of the front wall of said channel in the shape of a logarithmic spiral and permit the arc of admission to be amplified to such an extent that the water stream fills out said central space.

7 A water turbine comprising a drum having a series of vanes occupying a circumferential ring portion of said drum and a free central space within said series of vanes, a shaft in the centre of said space, an admission channel having its back wall curved near the drum in the form of a logarithmic spiral, a discharge channel joined to a circumferential portion of the drum opposite the mouth of said admission channel, and an adjustable flap positioned in said admission channel so as to form a continuation of the front wall of said admission channel in the shape of a logarithmic spiral. and permit the arc of admission to be amplified to such an extent that discharge takes place through all such passages between said vanes as have direct communication with said discharge channel.

In testimony whereof I mix my signature in presence of two witnesses.

ELEMER BANKI.

Witnesses:

D. ERNEST PENRY, J ULIUS SCHWARZ. 

